1. Field of the Invention
The present invention is directed to a ball throwing device for use in practicing tennis, baseball batting practice, and more particularly to a ball throwing device for throwing tennis balls, baseballs, and the like in a tossing or underhand manner.
2. Prior Art
There have been proposed a number of ball throwing devices in which a ball throwing arm is propelled such as by the biasing force of spring means to throw a ball in a given trajectory. For the purpose of tossing a flat ball or ball with less spin in a controlled manner for effective practicing and of keeping energy loss at a minimum, such device is required to have less frictional or loose-touch engagement between the ball and a ball receiving portion of the throwing arm.
However, the above attempt of reducing the friction will result in the failure of properly holding the ball of the arm, thus causing the ball to accidentally drop out from the arm before being thrown. To this end, the prior device for throwing the ball in a tossing or underhand manner has been devised to include a guide rail which extends in the path of the ball receiving portion of the throwing arm to be cooperative therewith for preventing the ball from dropping during the throwing stroke, for example, as shown in Japanese Laid-Open Publication No. 56 26427 and in U.S. Pat. No. 4,029,003. But, the addition of the guide rail will certainly result in the loss of energy built up in the throwing arm, thus lowering the speed thereof and therefore, reducing the distance travelled by the thrown ball.